How do I insert lines in the middle of a file

[Melsbacksfriend]

I'm trying to write a program that edits this .json in a noob-friendly way. I need it to put lines in between lines. What is the easiest way to do this?

[Repeater]

You copy the file, line by line, and when you get to the place where you want you new line, you write it. Then you keep copying.

[Duthomhas]

That, or simply load the file into memory, insert the line, and write the file back out.

Have you considered using a JSON library to help you out?

[Melsbacksfriend]

You copy the file, line by line, and when you get to the place where you want you new line, you write it. Then you keep copying.

How do I copy it line by line?

[Repeater]

You open the file that you want to read from, and you open a file to write to.

You read a line from the input file, using a function such as getline. Then you write it out to the output file.